Carburetor



C)y H. ENSGN Feb. H0, E933.

CARBURETOR 2 Sheets-Sheet l Filed June CSO 1925 IIN,

:IMU S y J l fdl,

w Inf/caa@ faille HZ/wf???- O. HQENSIGN Feb. 1 0, 1931.

CARBURETOR F'ilel June 30, 1925 2 Sheets-Sheet 2 FOM mima

Patented Feb. 10, .1931

UNITED STATES PATENT oFElcE COMPANY, OF LOS ANGELES, CALIFORNIA, ACORPORATION F CALIFORNIA CARBUBETOR Application filed June 30, 1925.Serial No. 40,532.

This invention relates particularly to improvements in Venturi plaintube type caruretor and moreparticularly to improvements on the type setforth in my copending application filed April 17, 1922, Serial No.

An object of this invention is to construct a novel carburetorwhich willsuccessfully operate, both under load and idling, at extreme angles fromthe normal vertical position without readjustment of the mixture. l

An object is to rovide a novel and simple `Venturi type car uretorhaving only one opening to the atmosphere.

Another object is to provide novel means whereby the volume of fuelmaintained in the accelerating well during idling may be increasedordecreased by the changing yof calibrated air bleeds.

Another object is to -provide a carburetor of this type 1n which the airresistance in the air horn is reduced to a minimum, thus'y avoldingirregular proportlonlng character istics which are imposed byobstructlons usually found immediately below the Venturi throat.

Features of this invention are in the provision of means whereby theflow of fuel during idlin same pati to the main air stream; and in whichthe idling mixture adjustment that operates on the load fuel orifice isso located with reference to the depression at the venturi that avariable adjustment of the idling mixture will not.Vy affect any loadmixture.

Other objects, advantages and features of invention may appear from theaccompanying drawings, the subjoined detail description and the appendedclaims.

I' `v preferable.

Figure 1 is .an axial sectional view of a -carburetor constructed inaccordance with" i positron. l

g The air intake may be provided with the this invention with thethrottle slightly open for light load and with the fuel at'restf Fig-1ais a fragmental sectional view showing a modified form of the atomizinglair and fuel passages.v Fig. 2 is an enlarged V fragmental sectionaloper a1 uel orifice 10,` .which ma and under load is through the' The,accompanying drawings illustrate the View of the fuel discharge nozzleas included in the form shown in F1g. Ia.

Fig. 3 is a section on irregular line .w3-a3, Fig. 1.

Fig. 4 is a section on line WiL-m4, Fig. 1, showmg the carburetor withthe float bowl andthe bracket containin the main fuel adjusting elementsremove Fi 5 is a section on reduced scale on line m5, ig. 1.

Fig. 6 is afragmental section showing the sustained column of fuel inthefuel passage during idling.

The carburetor is provided with an air intake 1, a suction passage 2controlled by a throttle -3, a 'constant level fuel chamber 4 suppliedwith fuelv through'th'e lusual fuel connections controlled by the valve6. A float 7 in the supply or fuel chamber 4 coates with the valve 6 tomaintain' the fueliin said chamber at a constant level 8.

Fuel is deliveredV from the constant level j fuel chamber to the suctionpassage through a fuel passage, '9"0 eninginto a suction chamber 11through be located at any suitable height in said riser, but ispreferably located near the upper end thereof. The riser 9 is spacedfromthe walls of't'he suction chamber 11 to provide'ample clearance for fuelandair flow. The-lower end of the's'uction chamber is extended in theform of aU-tube comprising a horizontal passage 12, which opens throughan inclined nozzle 13 to the main air stream slightly above the smallestdiameter of the Venturi throat 13.

The major portion of the fuel passage is which comprises afuel r1serformed in a bracket member A, which is secured by screws 14 to theflanged face of the main body member B, which contains the air intakeand suction passage. A member'v C that forms the constantlevel fuelchamber 4 is secured b screws l'r-to the member B and 'encloses t ebracket member when in member B secures the member 21 in the suctionpassage. l,

The nozzle 13 is provided with a threaded portion 23 ythat is threadedinto the mem-ber B and is also provided with a contracted extension 24that is received in and extends through' a- Calibrated clearance bore 25formed in and extending through one wall of the Venturi member. 21,which forms the Venturi throat. The bore 25 at the inner periphery ofthe Venturi member forms a definitei clearance around the extension 24of thefozzlev 13 and' is enlarged at the outer peri' hery of member 21as at 25 to form amp e clearance to permit flow of fuel there-l throughas will be more fully hereinafter ex lained.

n all the forms shown the nozzle 13 is provided with a bore enlarged atits entrance, that is to'say at the end into which the fuel enters saidnozzle from the suction chamber, as moreparticularly shown in Figs. 2and 6.

In ther form shown in Figs. laand 2 the horizontal passage 12 ofslightly smaller diameter than in the form shown in Fig. 1 and the endthereof adja cent the nozzle 13 isenlarged to form enlargement in thebottom of the U-tube fuel passage. The purpose of this enlargement willbe more fully hereinafter set forth.

An idlinV by-pass 26 opens throughan idling' fuel )et 27 tothe suctionpassage be yond the'throttle and is' continued by the cored passage 28,which is curvedat 29 to clear the nozzle 13, and is extended by anidling by-pass tube 30 toa sump 31 in the air intake. The lower end oftube 30 is provided with cross holes 32 to insure full opening of thetube 30 at its lower end.

The idling byass is connected to the en,-v largement 25 of re 25 by adrilled hole33. The idling by-passq26 is provided with a valved vent l34that opens into the main air stream at a point slightly below thesmallest portion of the Venturi throatand `is controlled by a suitableneedle valve'35, which is held in adjusted position by a spring retainer36.

The idling byass is provided with an adi edi; which opens into thecored"y passage 19 of the balancing means through ditional air ble thecalibrated plug or .vent 37. f

` The vent 37, the clearance bore 25, the bypass tube 30, constitutefixed vents to reduce the pressure in the idling by-pass 26 from of thefuel passage is by means of the calibrated idling 'depressioni passage38 the flow through which may be varied by changing the calibrated plug38. From the'foregoing itis apparentthat it is possible to adjust theidle mixture by means ofthe valve 35.

lAir is admitted from the lioat chamber to the suction chamber throughthe calibrated vent'39, and thereby provides means connecting the'suction chamber to the air intake through the balancing air passage.

Small holes 40 are provided` in the nozzle 13 and such' holes connectthe bore of the nozzle 13 to the enlarged clearance 25', and thu's bythe hole 33 to the idling by-pass and thus to the idling fuel jet 27.

The horizontal passage 12 of the fuel passage is connected to thepassage 38. by means of a supplemental passage 41, which is preferablyrestricted at its upper end. This passage provides additional'accelerating fuel and admits air from the upper end of the suctionchamber to the fuel passage near the nozzle 13, thus aiding in earlydelivery of accelerating fuel.

The member B is provided with aflanged face 42 in which a major portionof the idling by-pass 26 is formed by coring the member when the same iscast. f

A common asket 43 is interposed between the members l A and C rtoprovide an air and gasoline tight joint 'between such parts.

A acking 44 interposed between the top of member A and member C providesa tight joint between said members'around the opening 45 through whichextends the boss46 of member A and in which boss is threaded the highspeed adjusting needle 47 that adjusts the opening of the fuel orifice10.

l The member A is provided' wlth a bore forming the suction chamber andsuch bore is threaded at the lower end to receive the threaded portion48 of the riser 9, and thus y provides simple means for assembling thelVenturi to the carburetor flange y and such` lportion may i'nclude whatvhas heretofore een designated insome types of carburetors as a mixingchamber, ha mixture outlet and a Asuction passage.

, An annu/lar groove 49 formed in the wall of the air intake preventscondensed. fuel from running down the walls of the air in-Y take pastthe choke valve 16. j

.j throttle through the idling by-pass and any fuel falling down fromthe suction passage as the engine slowly stops is carried into theengine through the tube 30 and idling by-pass andthus prevents drippingof fuel fromthe carburetor after -the engine has stopped.

The construction shown 1n Fig. 1 is satisy factory for all heavy dutymotorswith relativel spee s.

The construction of the fuel passage and large displacement and moderatesupplemental passage 41 shown inFigs. 1a referable for such t pes of and2, is deemed motors that deve op a large amount 0 power from arelatively small displacement and at relatively highmotor speeds.

of the mental passage 41 air. fromthe calibrated vent 39 throughpaswhich again makes poso buretor is at rest at any justing needle 7 Dueto the small dis lacement of these high speed motors when i lin theyrequire very little fuel for idling an itv has been found difficult toform a seal in the lower portion U-tube fuel passage, when such fuelpassage is large enough to develop full power as with the device in Fig.1; and 1n such high speed motors I prefer to use the construction shownin Fig. la and in which the suppleis open to the passage 38 its fulldiameter asshown in Fig. 1a.

This passage/41 being open full size to the passage 38, without therestriction at the top, as shown in-Fig. l, allows the passage of moresage 41 underA load, sible the reduction in diameter of the horizontalportion 12 of the fuel assage so that this portion 12 is .just su amountof air.

The lower'v end of the passage 41 is extended to below the center. ofthe portion 12 tube 51, thus making of the fuel passage by a it possibleto readilyseal the fuel passage, when idling. i

In operation of the device shown in Fig. 1,

i fuel is supplied to the constant level fuel chamber 4 in the usualway'. When the. carl this fuel is protected from overflow -iuto the`suction chamber by the proper height ofthe top of the fuel riser 9above the constant fuel level 8.

Whenunder load with the throttle valve degree of open-ing above idlingthe normal flow of fuel is through the bore of the riser 9, thencethrough therestricted fuel orifice 10 under control of the high speedadinto the U- tube fuel passage comprising the suction chamber `11, intothe lower' end of whichthe' riser 9 extends and:

, forms an annulus betweeni the riser .and the iwalls of the suctionchamber thatlforms one limb of the U-tube, thence into the horizontal ApassageA and upwardly `inclined nozzle that applied ciently largeoenough for the flow of fuel and some smalll 13 from which the fuel isdischarged into the main air stream at the Venturi throat slightly abovethe smallest diameter ofthe Venturi throat,

' At the same time air will be drawninto the fuel assage vthrough thecalibrated vent ginning of delivery of fuel through the fuel nozzle 13.Y

When idling the throttle is closedand the depression in the'chamber 11is increased over in such chamber 11 through the nozzle 13; plied to thesuction chamber idlin fuel 'jet 27 and the idling by-pass 26 and. t ecalibrated idling depression passage 38 that opens fromthe idlingby-pass 26 into the suction chamber above the riser. This increaseddepression from above the throttle is modified by fixed bleeds yand bythe valved vent 34. 7

The idling luy-pass tube 3`constitutes one of these fixed bleeds andsuch bleed 30 performs the additional functioof conducting liquid fuelfrom the, sump 31 to the idling by-pass.' The definite clearance aroundthe discharge end ofthe nozzle 13 connected to the idling by-passthrough4 the-drill hole 33 constitutes a second fixed bleed and thecali.- brated plug 37, a third fixed bleed.

The first thus reduces ythe depression in the .idling ley-pass 26 adefinite amount below This increaseddepression is apthrough the j thatfrom above the throttle and the valved.

vent 34 under control of the needle valve 35 is used to control lor varythe reduction of the 'depression in the idling by-'pass bysuppleinenting the constant'or fixed bleeds by a variable bleed.

If the throttle is closed to idling position after the engine` has beenrunning any load or s eed'condition, the fuel moving through the elpassage becomes atrest in the horizontal iortion` 12 of the fuel passageand seals o the connection betweensuch horizontal portion and theannulus formed around the riser in thesuction'chamber. By thus sealingthe passage 12 the depression applied in the suction' chamber 11 throughthe idling by-pass will immediately rise invalue in excess of thedepression at the end of the'.

nozzle 13 in the venturi and such excess` in depression will sustaininthe suction chamber. and in the supplemental passagelil, i

against the force of gravity, the level of which is considerably highera column of fuelf` than the discharge end of the nozzle 13 and theheight of this sustained column offuel The fuel accumulated in thesupplemental iat I 39 and then, first .it will be drawn into the idlingand thence to bepassage 41 is sustained at the same or a greater heightthan the fuel in the suction chamber and provides additional fuel foracceleration purposes. y

Continued operation of the engine causes fuel to be lifted over the topof the riser from which it willbe added to the sustained column of fuelin the suction' passage and this addition of fuel will cause an equalamount of fuel to be displaced from the end of the nozzle 13 or throughthe small .holes 40 provided in the nozzle 13. The fueldischarged fromthe end of the nozzle 13 during idling will How in a small film aroundthe edge of the nozzle 13 and thence into the enlargement 25 at theinner end ofthe bore 25 from which bypass through the drill hole yondthe throttle where it is delivered to the suction passage through theidlin fuel jet 27. If for any reason the fuel emitted from the dischargeend of the nozzle 13 during idling should How down the side walls of theair intake, it will be stopped from flowing out of the air intake by theannular groove 49 from which it will be delivered to the idling by-passthrough tube 30.

Upon opening the throttle fuel immediately begins to discharge morerapidly from the nozzle 13 because the depression sustaining the columnof fuel in the suction chamber `and the supplemental passage has beenremoved, and such discharge of fuel is followed by air from the airintake through the vent A through the supplemental passage 41 and secondthrough the annulus in the suction chamber. The flow lof air through thesupplemental passage 4l begins atomizing the fuel at an early periodinthe discharge from the nozzle and as the engine gains speed the How ofair through the passage 41 and the annulus will gradually clean out allof the sustained fuel until the engine reaches a speed that will requireall of the passage 12 for the newly proportioned fuel and air under any'particular continuous load operation so that under any considerableload no fuel will remainin the fuel passage other than that continuouslysupplied for operation of the engine.

i The openings 40 upon closing the throttle to idling positionfacilitate immediately enriching the idling mixture by drawing directlyupon the fuel through the idling by pass until the fuel reaches theopenings-40 in solid form.

The size of the -openings 40 is such that when idling all ofthe fuelrequired to supply the. engine will not flow through such openings, butsome of the fuel will flow over the openings 40 and discharge from theend of the fuel nozzle 13 and be delivered to the engine as abofe setforth.

The air supplied to the constant level fuel chamber 4 and to the suctionchamber and fuel passage provides a balancing means to maintain apressure in the fuel chamber coordinating with that in the air intakeand is similar in many respects to the balancing system set forth in myPatent N o. 1,506,229, patented August 26, 1924.

The function of the various fixed bleeds for the idling by-pass isbelieved to be apparent to anyone versed in the art and thereore only abrief explanation of the same will be given. The calibrated vent 39 hasto do with the effectiveness of atomization and rapid delivery of thefuel sustained during idling for aceelerationpurposes. Enlarging thevent 39 increasesthe fuel economy and reduces the amount of fuelsustained for acceleration purposes.

The idling depression passage 38 has to do Withdeveloping the correctidling mixture. The bleed 37 has to do with refining the development ofthe idling depression changing the size of the passage 38. One drillsize may make too great a change in the idling mixture and leave theidling mixture beyond the control of the valved vent 34. Then, in orderto bring the idling mixture under the control of the valved vent thecalibrated plug or vent 3'( can be changed to a larger or smaller size,as the case may be. This function is'the main reason for the vent 37.

However, the vent'37 combined with the passage 38 performs anotherfunction. Enlarging the vent 37, all other things being constant,increases the depression applied on the surface of thel fuel in the fuelsupply chamber 4 during idling. Such depression is operatively effectiveon the fuel supply to the orifice 10 to bring about the same conditionas though the fuel level in the chamber 4 had been lowered and when suchdepression ,occurs the depression applied in the suction chamber l1 mustbe increased to draw the fuel'over the top of the riser 9, and when thedepression in chamber 11 is increased the height of the sustained columnof fuel is greater whenever the vent 37 is enlarged.

hen a good metering curve'and ood idling mixture is obtained, but thepic up from idling is' not quite satisfactory, enlarg-` ing the passage38 and then enlargingthe vent l37 to again bring the idling mixturewithin the control of the valved vent 34 will increase the height of thecolumn of fuel sustained in the fuel and supplemental passages and thusprovide the desired fuel for acceleration from idling speed Withoutrequiring any change in the dimensions of the parts containing suchaccelerating fuel.

The height of the 'fuel sustained in the auxiliary passage 41 isdetermined by the velocity head'through' the vent 39 andthe passage 38,.The higher the velocity the higher the column of fuel.

The operation of the device shown in Figs. 1a and 2 is practically thesame as above set forth with respect to the operation of they deviceshown in Fig. 1 except that upon closing the throttle after load toidling position,

fuel will immediately accumulatein the en. 5 largement n 50 of the fuelpassage and will be drawn with air .through the supplemental passage 4land the calibrated plug38 andl` the force of gravity and form anaccumulation of fuel which serves as accelerating fuel. When the fuelseals the portion 12 and the passage 41', immediately thereafter thefull idle mixture is obtained and the fuel will 20 flow through they nozzle 13 and be delivered in the normal way to the main air stream.

Upon suddenly opening the throttle due to the fact that the lower end ofthe tube 51 is nearest the nozzle, this portion of the acceleratng fuelis discharged quickest and is followed immediately by air from the vent39 through idling depression passa produces early atomization of l `elin the accelerating period. -1'

The remainder of the fuel accumulated in the fuel passage is slowlydelivered to the main air stream and continues to supply acceleratingfuel for a smooth aggressiveacceleration which is highly desired onmotors which obtain their maximumhorse power at E high motor speed withrathersmall displace-A ment. y

I claim; v i1. A carburetoromprising an air intake; 40 a throttlecontrolled suction paage; a constant level fuel chamber; a'fuel passagecomrising a suction chamber, a fuel riser openmg from said fuel chamberinto said suction.

chamber above the normal fuellevel; and a Utube portion 'connecting saidsuction chamber to'said suction passage; an idling by-pass leading fromnear the delivery endl of the fuel passage to the suction throttle; andcalibrated means supplying airv to said suction chamber.

2. A carburetor comprising an air intake; a throttle controlled suctionpassage;"a`con stant level fuel chamber; an idling by-pass leading fromnear'the'delivery end of 'the fuel passage to the suctidnpassage abovethe throttle; a fuel passage comprising a suction chamber; a fuel riseropening from said fuel chamber into said suction chamber above the`normal fuel leyel, anda U-tube portion conn w necting said suctionchamber to said suction passage; a passage connecting said suctionchamber an `means supplying air from said air vintake to ysaid suctionchamber; andA a valve controlled -05 passage open from the suctionpassage slight-*- e 38 and thus Y -..throat; anair intake,'.and athrottle con-v passage above the said idling by-pass 'calibrated 'andmeans connectin ly below. the Venturi throat'to said idling by-pass tocontrol the depression in the suction chamber when idling. V

3. Av carburetor comprising an air intake;

a throttle controlled suction passage; a constant level fuel chamber;.an idling by-pass; v

a fuel passage comprising a suction chamber,

a fuel riser opening'from said fuel chamber .for supplying-air to said-fuel chamber; and

" means connecting said idling by-pass with said fuel chamber above thenormal fuel level therein.

4.- In a carburetor, an air intake, a throttle controlled*suctionlpassage, a fuel passa e connected to deliver. fuel from a fuel supp y tosaid suction passage and comprising a suction chamber, a fuel riserIextending into said suction chamber above thenprmal fuel level andadapted to deliver-fuel b yoverflow into said suction chamber abovethenormal fuel level, said suction chamber being connected below theconstantA fuel level to the suction passageby a suitable nozzle; anidlin bypass connected near the delivery end o said uel passage andconnected to apply in said suction chamber a depression from beyond the-throttle to furnish fuel during idling;

said'sair intake with the fuel supply cham er andlwith said suctionchamber.`

5. A carburetor comprising a Venturi.. l

trolled suction passa e; a suction chamber; meansadapted to deliver fuelvto said suction chamber; a fuel passage adapted Lto deliver fuel fromsaid suction chamber to 'said sucltion passage; a constant level fuelfchamber supplied with air from the air intake and connected to saidmeans to suv.ply fuel to said suction chamber; an idling y'passconnected also connected to the suction chamber through' a calibratedpassage; saididling bypass being open througha calibratedplug tothepassa e connecting the air intake andthe fuel supp necting the idlingby-pa and the suction passage 'atla point fel Aagainst the force of oracceleration.v 6. -A.- carburetorI having a Venturi throat andcomprising an air intake; a throttle controlled suction passage; aconstant level fuel 1 chamber a fuel passage in the form of a U-tubeadapted to deliver fuel from said fuel to the suction passage abovethethrottle .and

y chamber; an adjustable vent conbelow the smallest diamchamber to saidsuction passage; there being an enlargement in the lower portion of theU-tube passage; an idling by-pass open from beyond the throttle; apassage connecting said idling by-pass intermediate its ends to saidsuction chamber above the normal fuel level in said fuel chamber; and asupplemental passage connecting the fuel passage below the center ofsaid enlargement to the lo passage that connects the idling by-pass tothe fuel chamber.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 24th day of June, 1925. 15 ORVILLE H. ENSIGN.

